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  <title>属性选择器</title>
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   h1[title] {
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      <article>
        <h1 title >后盾人</h1>
        <h2 >hdcms.com</h2>
        <aside>
          <h2>houdunren.com</h2>
        </aside>
        <h2>hdcms.com</h2>
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